Comparison of two disaccharides and their saccharide components in AOT reverse micelles: Impacts of D-trehalose and D-sucrose

Reverse micelles, featuring an AOT surfactant with a polar head group and nonpolar tail, encapsulate a polar phase at the nanoscale. With water as the polar phase, the nanoconfined water pool interactions and water-interface interactions mimic biological nanoconfinement. Thus, we investigated the impact of osmolytes on AOT reverse micelles to explore the role they play in biological systems. We investigated two disaccharides, D-trehalose and D-sucrose, and their monosaccharide components, glucose+glucose and glucose+fructose. We chose these molecules for their biological significance and to allow us to investigate whether subtle structural changes in the osmolyte impacts the intermolecular interactions in confinement as strongly as is found with monosaccharides (Halliday). In determining the size of reverse micelles, Dynamic Light Scattering (DLS) indicates saccharide-containing reverse micelles are smaller than reverse micelles with the same volume of water. Additionally, DLS shows there is no difference in reverse micelle size between D-trehalose and sucrose or their saccharide components. We further probed the system using a fluorescent dye molecule for lifetime measurements to determine the impact confinement and saccharides have on relaxation processes. Optical spectroscopy experiments, such as fluorescence anisotropy measurements, indicate relaxation processes are slowed by confinement and by increasing saccharide concentration. Similar to DLS results, there is seemingly no difference between the impact of D-trehalose and sucrose or their saccharide components on relaxation processes. Halliday et al. Langmuir. 2024.